A conventional television receiver (TV), as shown in FIG. 1, includes a first tuner 12 and a second tuner 13 for respectively selecting specified broadcasting signals for constructing a main picture and a sub picture among broadcasting signals received through an antenna 11, a first luminance/chrominance (Y/C) separating section 14 and a second luminance/chrominance (Y/C) separating section 15 for separating the broadcasting signals selected by the first tuner 12 and the second tuner 13 into chrominance signals and luminance signals, respectively, a scaler 16 for adjusting the size of picture with respect to an output of the first Y/C separating section 15, a color picture tube (CPT) 17, a video processing section 18 for mixing and video-processing outputs of the first Y/C separating section 14 and the scaler 16 to display the processed video signal on the CPT 17, a speaker 19, an audio processing section 20 for processing audio signals of the broadcasting signals selected by the first tuner 12 and the second tuner 13 to output the processed audio signal through the speaker 19, a sync separating section 21 for separating horizontal/vertical sync signals from the output of the first tuner 12, a control section 22 for controlling the scaler 16 to adjust the position and size of the sub picture, controlling the video processing section 18 to video-process the main picture signal according to the horizontal/vertical sync signals separated by the sync separating section 21, and controlling the audio processing section 20 to process the audio signal, and an EEPROM 23 for storing an operation program of the control section 22 and various kinds of set data.
The sub picture control operation of the conventional TV as constructed above will now be explained.
First, a user turns on the power of the TV, and selects one channel as the main picture and another channel as the sub picture.
Accordingly, the control section 22 controls the first tuner 12 and the second tuner 13, so that the first tuner 12 selects the channel broadcasting signal for the main picture, and the second tuner 13 selects the channel broadcasting signal for the sub picture.
Then, the main picture broadcasting signal and the sub picture broadcasting signal are separated into chrominance signals and luminance signals through the first tuner 12 and first Y/C separating section 14, and the second tuner 13 and second Y/C separating section 15, respectively.
The output of the second Y/C separating section 15 is inputted to the scaler 16, and the picture size of the sub picture is adjusted through the scaler 16 under the control of the control section 22.
The output of the first Y/C separating section and the output of the scaler 16 are mixed together and video-processed in the video processing section 18 under the control of the control section 22, and then displayed on a screen of the CPT 17.
Meanwhile, the audio signals of the broadcasting signals selected through the first tuner 12 and the second tuner 13 are processed in the audio processing section 20 under the control of the control section 22, and then outputted through the speaker 19.
At this time, as shown in FIG. 2, the whole sub picture according to the conventional technique is scaled to a predetermined size, and displayed on a corresponding position of the screen.
For example, if it is assumed that a character ‘A’ is the core element of the whole picture, this picture is scaled as it is and displayed as the sub picture, and the character ‘B’ is shown in the sub picture. As shown in FIG. 2, the character ‘B’ is so small that its shape cannot be almost recognized in the sub picture.
That is, according to the conventional TV, since the whole picture is scaled as it is and displayed as the sub picture, the core element of the sub picture cannot be accurately recognized, and the sub picture desired by the user cannot be obtained, causing the user's dissatisfaction.